Acid-catalyzed decomposition of aliphatic hydroperoxides

ABSTRACT

Tertiary aliphatic hydroperoxides and peroxides in the presence of a highly concentrated acid catalyst are converted to a mixture of ketones and alcohols in substantially quantitative yields. The corresponding secondary aliphatic hydroperoxides yield product mixtures of alcohols, ketones and aldehydes in varying proportions, depending upon the acid concentration employed.

'United States Patent Turner et al.

Nov. 4, 1975 AClD-CATALYZED DECOMPOSITION OF ALIPHATIC HYDROPEROXIDESInventors: John O. Turner, Shavertown;

Norman C. Deno, State College,

both of Pa.

Assignee: Sun Ventures, Inc., St. Davids, Pa.

Filed: Dec. 16, 1974 Appl. No.: 532,791

Related US. Application Data Division of Ser. No. 431,634, Jan. 8, 1974,Pat. No. 3,899,536, which is a continuation-in-part of Ser. No. 98,035,Dec. 14, I970, abandoned, which is a continuation-in-part of Ser. No.54,578, July l3, l970, abandoned.

US. Cl. 260/593 A; 260/632 R; 260/601 R Int. Cl. C07C 45/00 Field ofSearch 260/593 A, 601 R, 632 R, 260/632 C References Cited UNITED STATESPATENTS 11/1956 Joris 260/619 OTHER PUBLICATIONS Roberts et al., OrganicChemistry, pp. 431-432.

Deno et al., J. Org. Chem, Vol. 35(9), pp. 3080-3082, (1970).

Hoffman et al., J. Am. Chem. Soc., Vol. 77, pp. 3139 (1955).

Primary EXafrriiner JameS 0. Thomas, Jr.

Assistant ExaminerJames H. Reamer Attorney, Agent, or FirmGeorge L.Church; Donald R. Johnson; Stanford M. Back [57] ABSTRACT 3 Claims, NoDrawings ACID-CATALYZED DECOMPOSITION OF ALIPI-IATIC I-IYDROPEROXIDESCROSS-REFERENCE TO RELATED APPLICATION This is a division of applicationSer. No. 431,634,

filed Jan: 8, 1974, now U .S. Pat. No. 3,899,536. which in turn is acontinuation-in-part of US. Ser. No. 98,035 filed Dec. 14, 1970, nowabandoned, which in turn is a continuation-in-part of US. Ser. -No.54,578 filed on July 13, 1970, now abandoned, in the name of John O.Turner and Norman C. Deno and both entitled ACID- CATALYZEDDECOMPOSITION OF ALlPl-IATIC HYDROPEROXIDES.

BACKGROUND ,OF THE INVENTION This invention relates to a novel processfor the preparation of ketones or aldehydes, and alcohols. Moreparticularly, this invention relates to a'process' for the preparationof high yields of aliphatic alcohols and ketones by reacting tertiaryaliphatic hydroperoxides and peroxides with a highly concentrated acidcatalyst. In a further embodiment, secondary aliphatic hydroperoxideshave been found to yield mixtures of alcohols, aldehydes and ketones ofvarying .concentrations, depending upon the acid concentration employed.

Certain prior art teachings have shown that alkyl or aromatichydroperoxides may be contacted with acids to form variousreactionproducts, including alcohols and ketones, but the results have, at best,been characterized by low yields and mixtures of many differentproducts. Thus, for example, Lefiler, Chem. Revs. 45, 385 (1949),suggested that the only products obtainable from the action of acids ont-butylhydroperoxide would be isobutylene and hydrogen peroxide.Maslennikov et al., Tr. Khim i Khim Ternol, 59 (1965), on the otherhand, reacted t-butylhydroperoxide with benzene-sulfonic acid to obtainless than 10 percent each of acetone and methanol. Similarly, Hoffman etal., J. Am. Chem. Soc., 77, 3139 (1955) prepared neopentyl alcohol andacetone from isooctyl hydroperoxide using 65 to 70 percent H SO but theyield of both of these products together was only about 40 percent.Finally, Turner et al., in copending application .U.S. Ser. No. 2,681,filed Jan. 13, 1970, disclosed that when t-butylhydroperoxide wascontacted with 50 to 60 weight percent sulfuric acid there was obtaineda mixture of di-tbutylperoxide and hydrogen peroxide. It was also foundthat at 10 to 20 weight percent concentration of sulfuric acid, noreaction whatsoever took place.

Using aromatic hydroperoxides as starting materials, Davies et al., J.Chem. Soc., 2204 (1954) reported that xanthhydryl peroxide was obtainedby contacting glacial acetic acid with xanthhydryl hydroperoxide. Also,it is well known that cumene hydroperoxide forms a mixture of phenol andacetone using low acid concentrations, and essentially unusabledecomposition products at high acid concentrations, i.e. atconcentrations of above about 80 percent. See also, J. Chem. Soc., 3917(1956) which indicates that if cumene were treated under strongly acidicconditions-the ring would be extensively sulfonated. Y I

Thus, the possibility of obtaining high' yields of ketones, aldehydesand alcohols from aliphatic hydroperoxides using concentrated acidcatalysts is neither taught nor suggested by the prior art. Rather, theeffect of concentrated acids on aromatic hydroperoxides suggests acontrary result, as does the fact-that lower con- SUMMARY OFTl-IE'INVENTION In accordance with the. present invention, it has nowbeen found that'when tertiary aliphatic hydroperoxides andperoxides arecontacted with a highly concentrated acid catalyst, there is obtained amixture of ketones and alcohols in high yields.

It has further been found that when secondary aliphatic hydroperoxides.are reacted with varying concentrations of acid, the composition of theproduct mixture comprising alcohols, ketones, and aldehydes, is alsovaried markedly.

, DESCRIPTION OF THE INVENTION The reaction of the tertiary aliphatichydroperoxide with the acid may be conveniently carried out by slowlyadding the hydroperoxide (or corresponding peroxide) to the concentratedacid, preferably dropwise, at a temperature of about.0 to 20C, andpreferably from 0 to 109C in order to control this highly exothermicreaction. Under these conditions, the reaction takes place virtuallyinstantaneously. Under these conditions, also, the ratio of startingmaterial to acid is not critical ex-v cept for the fact that the acidshould be maintained in substantial excessof the hydroperoxide as it isadded to the acid in order that its concentration not fall below about75 percent. Desirably, the acid concentration should be maintained atabout 80 to 96 percent, and most preferably at concentrations of atleast about 90 percent when the starting material is a tertiaryaliphatic hydroperoxide, although oleum solutions may be employed ifdesired. At concentrations below about 75 percent, when starting with anhydroperoxide, increasing amounts of the corresponding peroxides areformed.

The acids which may be used in the process of this invention includehydrochloric and sulfuric, as well as fluorosulfonic acid, acid-treatedmolecular sieves and the-like. Of these, sulfuric acid and oleum arepreferred.

pending upon the acid concentration employed, be seen from the examplesbelow.

The tertiary aliphatic hydroperoxide and peroxide starting materialsinclude those compounds having from about 3 to 12 carbon atoms. Thetertiary alkyl hydroperoxides are preferred since they are generallymore reactive than the secondary compounds. Typical amongst the tertiaryalkyl hydroperoxides are such compounds as t-butylhydroperoxide,t-pentylhydroperoxide, isooctyl hydroperoxide, and the like.

When these compounds are treated in accordance with this process thereare obtained the corresponding ketones and alcohols, as for example,t-butylhydroperoxide or -peroxide yields acetone and methanol, whilet-pentylhydroperoxide or -peroxide yields acetone and ethanol.

In a further embodiment of this invention it has been found thatsecondary aliphatic hydroperoxide may also be reacted with concentratedacids of at least about percent concentration to obtain a productmixture of alcohols, ketones and aldehydes. However, unlike thetertiary, aliphatic hydroperoxides, the type of compound and theproportions thereof vary markedly deas will The reaction employing thesesecondary aliphatic hydroperoxides is carriedout in the same manner,with the same conditions and with the same acids as in the case of thetertiary compounds. That is to say, the process is generally carried outby adding the hydroperoxide dropwise into the acid at a temperature offrom to C. The ratio of hydroperoxide to acid is not critical butpreferably the acid should be present in substantial excess of thehydroperoxide to maintain an acid concentration of at least 70 percent,and preferably above 85 percent up to 100 percent, or in the case ofsulfuric acid, in the form of oleum.

Again, the acids may include hydrochloric, sulfuric,

fluorosulfonic acid and the like. Sulfuric acid is preferred.

- The secondary aliphatic hydroperoxides, and preferably the alkylhydroperoxides, include compounds having from about 3 to 12 carbonatoms. Typical amongst these are such compounds as 2-butylhydroperoxide,2-pentylhydroperoxide, 3-pentylhydroperoxide and the like.

When these compounds are reacted with a concentrated acid of at leastabout 70-75 percent, and preferably higher, there are obtained not onlyalcohols and ketones, but in some cases, as described below, aldehydesas well. For example, 3-pentylhydroperoxide or -peroxide yieldspropanal, 3-pentanone, and ethanol. It has been determined that thereason for this is that such a product mixture is the result of bothhydrogen and alkyl migration. It has further been found that therelative proportions of these products may be varied by varying the acidconcentration. Thus, for example, using 96 percent sulfuric acid, in thecase of 2-butylhydroperoxide, there is obtained a 4824814 percent yieldof 2-butanone; ethanol and acetaldehyde mixture; and methanol andpropanal mixture respectively; whereas, for example, using 70 percentacid there is obtained an 82:18 yield 2-butanone and anethanol-acetaldehyde mixture respectively; with no products formed as aresult of methyl migration. As stated above, unlike tertiary aliphatichydroperoxides, the reaction of secondary hydroperoxides with acids thusvaries with acid concentration and, depending upon the nature of thestarting material, will produce aldehydes as well as alcohols andketones.

It will be understood that in each case where an alcoho] is formed, itis generally recovered as a salt corresponding to the acid employed.Thus, for example, when using sulfuric acid the ethanol is formed asethyl hydrogen sulfate. The product mixture of ketones, aldehydes andalcohols may, if desired, be readily separated by treating the reactionmixture with a strongly alkaline material such as sodium or potassiumhydroxide, followed by distilling and/or extracting and distilling theketones from the alcohols.

In still another embodiment of this process, it has been found when theacid catalyst employed is a peracid of the same concentrations asdescribed above, such as persulfuric acid or a mixture of e.g. I(,,S Oand H SQ, it is possible to form the desired hydroperoxide startingmaterial in situ from the corresponding alcohol. Thus, for example, whencontacting t-butyl alcohol with a molar equivalent of persulfuric acid,there is obtained a mixture of acetone and methanol. It has also beenfound, in accordance with this process, that when an excess of theperacid is used, and preferably at least 2'moles of acid, the acetone isfurther converted to acetic acid and additional methanol.

It will be understood that inasmuch as the process of this furtherembodiment involves the formation of hydroperoxide intermediates, insitu, that therefore the above-mentioned distinction between thetertiary alkyl hydroperoxides and secondary alkyl hydroperoxides appliesequally to the reaction involving the corresponding alcohols. That is tosay, when tertiary alkyl alcohols are reacted with peracids atconcentrations of at least about 90 percent, based on the weight of thetotal reaction mixture, the products obtained are ketones and alcohols,while the products of the corresponding secondary alkyl alcohols with aperacid of at least percent concentration are ketones, aldehydes, andalcohols.

The following specific examples will further serve to illustrate thenature, operation and advantages of the present invention. Allpercentages are on a weight basis. The reported yields are based onpercent conversion of the hydroperoxide starting material.

In these examples, Examples l-7 represent reactions employing tertiaryaliphatic hydroperoxides, while Examples 8 and 9 represent the resultsobtained from secondary hydroperoxides.

EXAMPLE 1 The following comparative example illustrates the resultsobtained by contacting an hydroperoxide with 50 weight percentconcentration of H SO Nine grams (0.1 moles) of t-butylhydroperoxide areadded to 25 cc of 50 weight percent aqueous H S04 and stirred at 50C for15 hours. Phase separation yields 6.75 g. (0.046 m) ofdi-t-butylperoxide (92 percent of theory) and a water white acid phase.

EXAMPLE 2 Four and one-half grams (0.05 moles) of t-butylhydroperoxideare added dropwise with stirring to 12 cc of 96 percent I-I SO whilemaintained the temperature below 15C. The hydroperoxide rearranges togive a 96 percent yield of acetone and methanol (analyzed quantitativelyby NMR spectroscopy).

In accordance with the foregoing procedure, but substitutingt-pentylhydroperoxide for t-butylhydroperoxide, there is obtained amixture of acetone and ethanol in 84 percent yield, together with lesseramounts of methylethyl ketone and methanol.

Also, in accordance with the foregoing procedure, but substitutingisooctylhydroperoxide for t-butylhydroperoxide, there is obtained amixture of neopentyl alcohol and acetone in an 85 percent yield.

EXAMPLE 3 Seven and three tenths grams (0.05 moles) of di-tbutylperoxideare added dropwise with stirring to 12 cc of 96 percent sulfuric acidwhile maintaining the temperature below 15C. The peroxide reacts in amanner to yield 0.049 moles of both acetone and methanol. The remainingpart of the peroxide molecule evolves as isobutene. When run underconditions which prevented loss of isobutene, isobutene polymerizationand rearrangement products (cycloallylic carbonium ions) are alsodetected in the NMR spectrum.

In accordance with the foregoing procedure, but substitutingdi-t-pentylperoxide for t-butylperoxide, there is obtained predominantlya mixture of ethanol and acetone.

EXAMPLE 4 When the procedure of Example 3 is repeated but.

percent fuming H SO is substituted for 96 percent H SO the same productsare obtained, i.e. acetone and methanol, together with some isobutene.

EXAMPLE 5 In accordance with the procedures of Example 2, butsubstituting fluorosulfonic acid for sulfuric acid, there is obtained amixture of acetone and methanol in 96 percent yield.

Similarly, when perchloric acid is substituted for sulfuric acid inExample 2, a high yield of acetone and methanol is once again obtained.

EXAMPLE 6 Addition of 0.15 grams of t-butyl alcohol to 2 moles of a K SO H SO reagent (made by dissolving grams of K 8 0 in moles of 96 percentH 80 yields predominantly acetone and methanol (as methyl hydrogensulfate) as shown by NMR spectra.

In accordance with the foregoing procedure, but starting with a molarexcess of acid reagent, there is obtained a mixture of acetone,methanol, acetic acid and some small amounts of methyl acetate, as shownby the NMR spectrum.

EXAMPLE 7 In accordance with the procedures of Example 7, butsubstituting t-amyl alcohol for t-butyl alcohol, there is obtained amixture of acetone and ethanol. When an excess of acid is employed, amixture of acetone, ethanol, acetic acid and some methanol is obtained.

EXAMPLE 8 A series of runs is carried out wherein 0.93 grams (0.01moles) of 2-butylhydroperoxide (92 percent pure) is added dropwise withstirring to 5 cc of sulfuric acid of the following concentrations: 70,80 and 96 percent while maintaining the temperature below 10C. The molepercent yield of products is as follows:

(a) Z-butanone resulting from hydrogen migration (b) ethyl hydrogensulfate and acetaldehyde resulting from ethyl migration (c) methylhydrogen sulfate and n-propanal resulting from methyl migration EXAMPLE9 In accordance with the procedures of Example 9, a series of runs iscarried out with 3-pentylhydroperoxide in place of 2-butylhydroperoxide.The mole percent yield of products is as follows:

Acid Hydrogen (a) Ethyl (b) Concentration Migration Migration 1 20 7O 3096 3O l 5 70 86 l4 (a) S-pentanone from hydrogen migration (h) ethylhydrogen sulfate and propanal from ethyl migration We claim:

1. A process for the preparation of ketones, aldehydes and alcoholswhich comprises contacting a secondary alkyl hydroperoxide or peroxidecontaining 3 to 12 carbon atoms at a temperature of from about 0 to 20Cwith an acid having a concentration of at least about 70 percent basedon the weight of the total reaction mixture, wherein said acid isselected from the group consisting of hydrochloric, sulfuric, oleum,fluorosulfonic and perchloric acid.

2. The process according to claim 1 wherein the acid concentration isfrom about 80 to 96 percent.

3. The process according to claim 1 wherein the hydroperoxide is3-pentylhydroperoxide and the product comprises a mixture of3-pentanone, propanal, and ethanol.

1. A PROCESS FOR THE PREPARATION OF KETONES, ALDEHYDES AND ALCOHOLSWHICH COMPRISES CONTACTING A SECONDARY ALKYL HYDROPERIOXIDE OR PERIOXIDECONTAINING 3 TO 12 CARBN ATOMS AT A TEMPERATURE OF FROM ABOUT 0* TO 20*CWITH AN ACID HAVING A CONCENTRATION OF AT LEAST ABOUT 70 PERCENT BASEDON THE WEIGHT OF THE TOTAL REACTION MIXTURE, WHEREIN SAID ACID SSELECTED FROM THE GROUP CONSISTING OF HYDROCHLORIC, SULFURC, OLEUM,FLUOROSULFONIC AND PERCHLORIC ACID.
 2. The process according to claim 1wherein the acid concentration is from about 80 to 96 percent.
 3. Theprocess according to claim 1 wherein the hydroperoxide is3-pentylhydroperoxide and the product comprises a mixture of3-pentanone, propanal, and ethanol.